Isolation and identification of potential probiotics bacteria from milkfish (Chanos chanos Forskal) gut in Gresik Regency, East Java, Indonesia

The present study was conducted to isolate and identify probiotic bacteria from the gut of milkfish (Chanos chanos Forskal). Six milkfish (65-70 g) were collected from 2 traditional freshwater ponds in Ujung Pangkah, Gresik Regency, East Java, Indonesia. Isolates of bacteria were collected and purified. The morphological characteristics of bacteria were observed, including gram reaction, cell shape, colony shape, elevation, color, optic and motility. Microbact identification kits 24A and 24B were used to identify the biochemical characteristics of bacteria. The enzymatic activity of bacteria was assessed to determine the ability of bacteria to produce amylase, cellulase, protease and lipase enzymes. Results showed that 14 isolate bacteria encoded BL1.1, BL1.2, BL1.3, BL1.4, BL1.5, BL1.6, BL2.1, BL2.2, BL2.3, BL2.4, BL2. .5, BL2.6, BL2.7 and BL2.8 were obtained from the milkfish gut. These isolates had similarities with 3 genera of bacteria, such as Bacillus sp., Pseudomonas sp., and Enterobacter sp. BL2.6 isolates have similar characteristics to Bacillus, producing high amylase and cellulase enzymes, with a high amylolytic and cellulolytic index of 6.39 and 0.06, respectively. The bacterial isolates detected in this research could be used as potential probiotics bacteria.